Implement pyrite-read CLI Entry Point
Complete the read-only CLI tier for agent safety. The three-CLI architecture (pyrite, pyrite-read, pyrite-admin) is described in documentation and help text, but `pyrite-read` is not registered as a `[project.scripts]` entry point in `pyproject.toml`.
Scope
Rationale
AI agents (Claude Code, Gemini CLI, Codex) use the CLI as their primary Pyrite interface. A read-only binary prevents accidental writes during research/exploration workflows. This completes the three-tier access model that MCP already enforces at construction time.